Service-observing equipment for automatic telephone systems



Nov. 3 1925. v 1,559,659

I J. N. WALTERS I 1 v 1 SERVICE OBSBRVING EQUIPMENT FOR AUTOMATIC TELEPHONE SYSTBIS Filod June 27-, 1923 INVENTOR' 6 ATTORNEY Patented Nov. 3, 1925.

UNITED STATES I 1,559,659 PATENT. OFFICE.

JAMES N. WALTE S, 01 EAST ORANGE, NEW JERSEY, AssIGNoR To AMERICAN TELE- PHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

SERVICE-OBSERVING EQUIPMENT FOR AUTOMATIC TELEPHONE SYSTEMS.

Application filed June 27, 1923. Serial No. 648,083.

To all whom it may concern:

Be it known that I, JAMES N. WALTEns, residing at East Orange, in the county of Essex and State of New Jersey, have in- 5 vented certain Improvements in Service- Observing Equipment for Automatic Telephone Systems, of which the following is a specification.

This invention relates to service observ- V ing equipment adapted to be associated with the circuits of an automatic telephone system.

In the service observing equipment heretofore utilized in mechanical or automatic oflices it has been the practice to employ a series relay for operating the relay equipment which connects the call to the observing operators desk and also for repeating the pulses from the calling dial at the sub- 0 scribers station. The use of the series relay makes it necessary to open the subscribers line at some point in the central oflice in order to place the-observing trunk in series with the line. In panel type ofiices where line finders are used and in step-by-step offices this connection is made at the main frame by removing the heat coils and inserting a plug which connects the observing trunk in series with the subscribers line. In panel type oflices where line switches are used, this connection is made at the intermediate frame and necessitates opening a cross-connection and placing two plugs over the terminal strips in order to get the observing trunk in series with the line. In addition to this in all types of mechanical ofiices, it is necessary to make a second connection to the sleeve and message register wires. There are many disadvantages in 40 this method of plugging up lines for service observation. One of these is that the number of jack boxes required in order to make the observing trunks accessible to any line is quite large and these boxes take up va1uable space on the frames and are so located that they interfere with the work of running cross connections. Another disadvantage lies in the fact that the long patching cords draped down the frames are continuously in the way of the frame man. Furthermore a great amount of time is required to put lines up and the cost of the equipment is relatively large due to the number of jack boxes required, cabling and costly plugs. Another'material disadvantage consists in the fact that the danger of interrupting the service is always increased where subscribers lines must be opened up.

The arrangements of the invention obviate the above mentioned difficulties and disad-- central ofiice apparatus. Accordingly the invention provides a bridged connection, or circuit, having included therein a vacuum tube amplifier. amplifier would be included a relay which would respond to the dial pulses and which might in turn operate a. register apparatus. Operatorslistening apparatus might also be associated with the plate circuit of the tube. The impedance 'presented by the input circuit of the vacuum tube would be In the plate circuit of the sufliciently great so that the service observ- I ing equipment would not interfere with the line or central ofiice equipment and the arrangements at the same time would be sufliciently sensitive to accurately repeat the dial pulses. Other features and advantages of the invention will be clear from the de-v tailed description hereinafter given.

The invention may be more fully understood from the following descriptiontogether with the accompanying drawing in which is illustrated a circuit diagram embodying the invention.

In the drawing is shown the tip, ring, sleeve, and message register conductors of a subscribers line terminating at ,a mechanical oflice. Conductors are bridged across these conductors at a suitable point in the central oflice and terminate in-the jack J. Adapted to cooperate with jack J is the plug P. When the plug P is connected with jack J the conductors 6 and 7 are bridged across the tip and ring conductors of the line and conductors 25 and 26 are bridged across the sleeve and message register conductors of the line respectively. The conductors 6 and 7 are associated over the contacts of relay 3 with conductorsfi and 9 Which terminate in the Winding of trans former 10. The other Winding of transformer 1O isincluded in the input. circuit.

of the Vacuumtube amplifier, 11. Theout u ofthepolar relay 14, which relay Will? con;

trola circuit 15 includingregister apparatus 16 and 17. 1

The arrangements operate in the followin manner: \Vhcn 3ld 'BlS- connected With jack J the relay 1. will'operate in parallel. withthe line relay of" the subscriberl's line over. a circuit including conductor 51-, armature and contact of. relay 2, conductor 5, Winding of relay 1, battery and. ground. The operation o'tvrelay 1 will close the fol. lowing circuit: from ground, contact and armature of relay 1, left handwinding. ofrelay 3, conductor 20, contact and armature of? relay 1,8, conductor 21, winding of relay 22, tov battery and ground. 1 This will oper atemelay Which will lockup over. the; fol? lowing circuit: from. ground and: battery, righthand-Windingof relay 3, contact; and; armature ofarelay 3, Winding of relay 18,

- and'over the contact; of release ,key. l9: to

ground. This Will operate relay 18: Which will open at its left hand contact the pre viously,traced-circuit through relay 22. The relay :22 controls a circuit 23 Which-may control c ycle counter apparatus i't'idesiredz The operation of relay 3 will connect 'oon.-. ductors- 8 and 9 to conductors 6 and 7 and; bridgethe primary Winding oi transformer lfl across the tip? and ring, conductors of the line, The polarrelay 14: in theplate circuit ofthe tube is normally energized; At each; interruption of the subscribers dial: the polarized relay 14; releases due to the relay action of the. tube which interrupts the current'i-n thev plate circuit. At each release of the polarized relay 14v the pen register apparatus; 16 and 17 Will b6 operated, oyencircui-t 15;. The operation of relay givill lightthe signal lamp 24: and willkconr nect conductors 29 andSO, Whichlea'd to message register lamps, to con ductors 27 and 28 which may be. selectively connected to conductor 26 and-thence to the messagerege ister conductor M of the line depending upon, the actuation cit-relay; 2; The actuation; oi relayr2- depends on the condition of the sleeve ofthe line. By openingthe releasekey 1:9 thev apparatusmay be restored tonormal; -V hile the arrangements of: theinvention have-been disclosed in certain specific an The plate rangcments which are deemed,desirable it is iuiderstood that they arecapable on embodiincntin many and widely varied forms with out departing" rom,the spirit oil the inyenr tion, asdefiuedhy the appen"d claims.

hat is'cla'i'med is: V

* naau oma ic eleph ne-sys em,

lin terminating'at a central ofiice, f-ngcircuit, switching means central oilice for bridging said observing circuit across said line, said 0111-, serving circuit inc 1d a:vacuum;tuheaniplifier and apolarued i lay in; the plate cir; ;uit of said tube;

2. .lnajn aatcmatictelephonesystem, 27$ll-hr. scrihers; line te minat ng at; de t QfiiQ d. c mprising tip 5 and; ngqnduct a pair of conductors associated with. saidg tip and: ring; conductorsv and ter I ll ting; in switchingmeans, service. observii equipment adapted; tobe; associated Witlr-sa' switching means, said equipment comprising a circuit inchiding a f vacuum tube amplifier,

polar zed relay in the plate rcuit tsaids tube, register pe ratusj controlled hy saijd;

, relay, and means lnsaid: equipment -nespon,-,

cu-it o'f-said tube.

4; In an automatic telephonesystem, afsub scribers line terminating. at aycentnals ofliQe and comprising tip and ring conductors, a; pair of conductor-s associated ithsaid-tip; and ringconductors and terminating; insW-itch-ing--means, service observing equipment adapted; to be associated with said switching means, said equipment comprising a circuit including a vacuum tube amplifier, a polariizcdgrelay in the-plate circuit: of said tube, register; apparatuscontrolled by said relay, means in. said; equipment responsive tothe closin of the subscribers line circuit 5 for operati vely associating sai'dwacuum tube circuit withsaid pair! ofconductors through said switching means, and-signal meanscontrolled by said last mentioned means.

"In testimony whereof", I; have signed my name to, this specification this, 26th day of June, 1923,. 7

JAMES N. 'lVAL'DER-S. 

